The present invention generally relates to an arrangement for a film cartridge for use in a photographic camera, and more particularly, to a camera of the above described type arranged to show different modes when a film cartridge of an unused state and that of a used state are loaded therein.
Conventionally, there has been shown in Japanese Patent Laid-Open Publication Tokkaihei No. 2-114248, a camera system employing a film cartridge of a new type, in which different from a known film cartridge, the film is entirely accommodated in the film cartridge main body, and loading of the film onto the camera is automatically effected by rotating a fork and a spool engaged therewith by a motor. Therefore, it is difficult to judge, from external appearance, whether the film cartridge is in an unused state or in a used state. Accordingly, there is a possibility that photography is effected with a cartridge in the used state being loaded on the camera, thus undesirably resulting in double exposure.
In order to avoid such a disadvantage, it has been proposed to give different indications on the film cartridges between the used state and the unused state thereof. However, in the case where a user is unaware of such indications, etc., the possibility of double exposure can not be completely eliminated. Therefore, there has also been proposed an arrangement in which, by setting rotational angle positions of the spool to be different between the used film cartridge and the unused film cartridge, the spool is adapted not to engage the fork at the camera body side in the case of the used film cartridge (based on an assumption that an initial position of the fork is normally set to be at a predetermined rotational angle position, i.e. at the position corresponding to the spool of the unused film cartridge).
In the above arrangement, however, it has been still possible that the user forces the used film cartridge into a film cartridge accommodating chamber of the camera body, thereby damaging associated mechanisms or parts, etc. Furthermore, for preventing such damage, it has been necessary to preliminarily improve mechanical strength of the parts such as the fork, etc., which may result in higher cost.